Sensitivity of fission barrier heights to nuclear matter properties

Abstract

We systematically investigate the correlations between nuclear fission properties and the surface energy coefficient $a_{\mathrm{surf}}$ extracted from semi-infinite nuclear matter. To this end, we employ the covariant density functional theory based on a point-coupling energy density functional (EDF). Taking ${}^{240}$Pu and ${}^{236}$U as representative examples, we employ Gaussian-process emulators to construct the joint posterior distributions of $a_{\mathrm{surf}}$ and selected fission observables, constrained by the ground state properties of the two nuclei. The results reveal a strong correlation between $a_{\mathrm{surf}}$ and the fission barrier heights. A sensitivity analysis further shows that the height of the outer fission barrier is governed predominantly by the isoscalar-vector derivative coupling constant ${\delta }_V$ in the point-coupling EDF, whereas that of the inner barrier is by the combined effects of ${\delta }_V$ and several mutually correlated coupling constants.

Comments: 14 pages and 6 figures in the main text, 9 pages and 9 figures in the Supplemental material